Initializing varibles from array in JavaScript

Question

I want to declare and assign default values to variables

let country, state, fruits;
let checkBoxfields = ['country', 'state', 'fruits'];
checkBoxfields.forEach(field=>{
    if(some condition){
        return field = true;
    }else{
        field = false;
    }

I want final output as such

country = true;
state = false;
fruits = true;

Can you add more information about what problem you are having implementing this? — bart cubrich
– bart cubrich, Commented Oct 30, 2019 at 22:39

Abito Prakash · Accepted Answer · 2019-10-30 19:03:15Z

3

You can create an empty object and then iterate over the checkBoxFields and then populate the object as needed

const obj = {};

const checkBoxfields = ['country', 'state', 'fruits'];
checkBoxfields.forEach(field => {
    if (some condition) {
        obj[field] = true;
    } else {
        obj[field] = false;
    }
});

Sample output

console.log(obj); // {country: false, state: true, fruits: true}

edited Oct 30, 2019 at 19:03

answered Oct 30, 2019 at 19:00

Abito Prakash

4,8002 gold badges16 silver badges28 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Rohit Hannurkar Over a year ago

I don't want object, I want a direct variable with value

Abito Prakash Over a year ago

Are these variable declared in global scope ? @RohitHannurkar

Rohit Hannurkar Over a year ago

Yes the declaration is in global scope

Abito Prakash Over a year ago

You can take out the variables by using const {country, state, fruits} = obj

Rohit Hannurkar Over a year ago

Yes I will go with this answer, thwnk you @Abito

Code Maniac · Accepted Answer · 2019-10-30 19:11:32Z

2

If the structure is consistent and value are always in the same order, then you can map and destructure value in variable with desired name something like this

let checkBoxfields = ['country', 'state', 'fruits'];
let [country, state, fruits] = checkBoxfields.map(field => {
  return field === 'country' || field === 'fruits'
})

console.log(country, state, fruits)

If the variables are defined in global scope you can use window to reference variable, That being said you should avoid using global as much as possible it has it's own drawback, makes code so hard to debug

var country, state, fruits;
const checkBoxfields = ['country', 'state', 'fruits'];
checkBoxfields.forEach(field => {
  if (field === 'country' || field === 'fruits') {
    window[field] = true;
  } else {
    window[field] = false;
  }
});


console.log(country,state,fruits)

edited Oct 30, 2019 at 19:11

answered Oct 30, 2019 at 19:07

Code Maniac

37.9k5 gold badges44 silver badges65 bronze badges

3 Comments

Rohit Hannurkar Over a year ago

No! The structure may change, based on the condition

Code Maniac Over a year ago

@RohitHannurkar the other answer is pretty much what you need in that condition

Rohit Hannurkar Over a year ago

Thank you @CodeManiac for the Answer, I will be going with Abito answer, considering the variables are not declared in global scope as you rightly said it has its own drawback and hard to debug

Collectives™ on Stack Overflow

Initializing varibles from array in JavaScript

2 Answers 2

5 Comments

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

5 Comments

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related